Thermal Modeling and Ampacity of Submarine Three Phase AC Cables with Lead Sheath: IEC 60287 versus Hybrid Analytical-FEA Approach

Accurate thermal rating of submarine power cables remains challenging because losses and heat dissipation depend on geometry, materials, and installation conditions. The IEC 60287 standard series offers a widely adopted analytical framework for steady-state ampacity, but relies on some simplifying assumptions. This work evaluates the fidelity of IEC 60287 against a hybrid analytical-FEA approach using a 2D thermal FEA model in an open-source software and public Lua scripts that model buried submarine AC cables with lead sheaths. In the hybrid analysis, IEC-based analytical formulas are used to calculate electrical losses (including skin/proximity factors), and these losses are then applied as heat sources in the thermal FEA model. Conductor resistance is updated iteratively for temperature convergence, while thermal property assumptions are kept consistent with the analytical approach to enable a like-for-like comparison. It is shown that the hybrid analysis tends to predict higher conductor temperatures than IEC, with the dominant discrepancy linked to differences in extracted thermal resistances